I saw the youtube video with Sean O'Hair. I hope you will admit there is a big difference between a professional golfer at or near the top of the game who looses their way and a mid-teen handicap who never had much of a way to begin with! 
Yes. The professional earns a living based on how well he plays the game. The mid-teen handicapper does not. Huge difference.
The fact is the great majority of golfers, assuming they have a real desire to improve, could benefit with some quality instruction and a good practice regimen.
When you say "benefit" that is totally defined by your assumption of a "desire to improve". There are many possible benefits to golf and most of them have nothing to do with "improve". Your perspective is locked into to a high-achiever mindset that may be deeply meaningful to you or it may simply be a habit that carries over from you other life experiences. Or both. But it's not the only mindset that brings people out onto a golf course.
I did not take up the game to improve myself, test myself, prove anything, master a skill, accomplish any goals or strive toward some unattainable standard of perfection. I tried it for the first few times as a non-boring way to get some mild physical activity and relaxation. Turns out, it worked fine for that purpose but beyond that I also just enjoyed the entire experience of being out there knocking the ball toward the hole and I enjoyed the surroundings of a golf course (even though it was a terribly undistinguished "pastureland" course with zero architectural merit).
From almost the first day I pick up a golf club I've been surrounded by well-intentioned people advising me to do this or that "or else I'll never get better at the game". There was a point a decade or so in where my interest in the game almost got derailed by forcing myself deeper and deeper into that aspirational way of thinking. Sort of a hacker's version of Sean O'Hair's period of wandering in the wilderness.
Examined from that mindset, those 2-1/2 years were my most "successful" time in the game. I knocked about 8-10 strokes off my handicap, started flirting with breaking 80, developed a bit more distance and even was able to draw the ball for the first time in my life. Another couple years on that road and I think I might have eventually been a consistent 70's shooter instead of a bogey golfer.
But you know what? I found myself playing less golf because of the time taken up by lessons, practice, working out in the gym and all sorts of "getting better" requirements that I purely hated. I was literally spending as much or more time doing stuff that I did not enjoy a bit as I did on the golf course doing what I loved. It was sheer madness! Along about that time I lost a couple of close family members, including one who died after a lingering and debilitating illness. I know it's a cliche but those losses opened my eyes.
So my advice is, if you enjoy "getting better" or you like to practice then that's a great hobby to spend your time on. But if only want to "improve" because you think the game is innately more enjoyable or worthwhile with a 5-handicap more than it is with a 15-handicap I'm here to tell you that's an illusion.